Add a notice for gdb debugging in component builds

Since obj files are loaded lazily, in order to set up breakpoints for a
component build, the program needs to run at least once. Add a notice
regarding this behaviour.

Bug: 1044564
Change-Id: Id2b90ebcbc658d1d2ad84b4fb8d09ac9a83e16db
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2014967
Reviewed-by: Nico Weber <[email protected]>
Commit-Queue: Henrique Ferreiro <[email protected]>
Cr-Commit-Position: refs/heads/master@{#734446}
diff --git a/docs/gdbinit.md b/docs/gdbinit.md
index d52735e..707cf1da 100644
--- a/docs/gdbinit.md
+++ b/docs/gdbinit.md
@@ -11,3 +11,8 @@
 ```
 source /path/to/chromium/src/tools/gdb/gdbinit
 ```
+
+*** promo
+Notice that in components builds, the debug files will be loaded lazily. Because of this, the program needs to run at least once before breakpoints can be set. Alternatively, gdb will ask for confirmation as follows:
+> Make breakpoint pending on future shared library load? (y or [n])
+***